Laser containing an organic dye lasing composition

ABSTRACT

A laser containing an aqueous dye lasing solution is disclosed wherein the dye solution contains a disaggregating compound which provides enhancement of the lasing output.

United States Patent [1 1 Herz et a1.

n 1 3,818,371 June 18, 1974 LASER CONTAINING AN ORGANIC DYE LASINGCOMPOSITION [75] Inventors: Arthur H. Herz; William C.

McGolgin; John S. Hayward; Otis G. Peterson, all of Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

221 Filed: Oct.18,1971

21 App1.No.:190,335

Related US. Application Data [63] Continuation of Ser. No. 29,027, March30, 1970,

abandoned.

[52] US. Cl 331/945 L, 252/3012 R [51] Int. Cl H015 3/14, C09k 1/02 [58]Field of Search 252/3012 R; 331/945 L Peterson et 211., Applied PhysicsLetters, Vol. 17, No. 6, p. 245-247, September, 1970.

Primary Examiner-Edward J. Meros Assistant Examiner.1. Cooper Attorney,Agent, or FirmDennis M. DeLeo [57] ABSTRACT A laser containing anaqueous dye lasing solution is disclosed wherein the dye solutioncontains a disaggregating compound which provides enhancement of thelasing output;

9 Claims, N0 Drawings 1 LASER CONTAINING AN ORGANIC DYE LASINGCOMPOSITION This is a continuation of application Ser. No. 24,027, filedMar. 30, 1970, now abandoned.

This invention relates to laser systems and more particularly to lasersystems using solutions containing organic dyes as lasing media.

Lasers (acronym for light amplification by stimulated emissionradiation) or optical masers (acronym for microwave amplification bystimulated emission radiation) are light amplifying devices whichproduce high intensity pulses of coherent monochromatic lightconcentrated in a well collimated beam commonly called a laser beam. Thelaser beam has found wide application in photography, communications,industrial measuring instruments and the like.

Various materials have been used as lasing media. A promising field hasbeen opened in the lasing of organic dye solutions. Some of the recentwork in this field is described by P. Sorokin, et al in Journal ofChemical Physics, Vol. 48, No. l0, May 1968 and Scientific American,Feb. 1969, pg. 220 et seq, and B. B. Snavely, Proceedings of the IEEE,57, 1374, 1969.

For many dye laserapplications it is desirable to produce continuouslaser beams or beams having a high frequency of output pulses. The highpower input required for such purposes tends to produce undesirableeffects in organic solutions of organic dyes. For example, high powerinputs tend to produce temperature gradients in organic solvents whichcan produce optical inhomogenities. These phenomenon can substantiallydecrease lasing efficiency.

A potential solution to the problems produced by high frequencyexcitations is the use of water as a dye solvent. The use of water hasbeen frustrated due to the fact that many organic dyes which lase inmediums such as alcohol were either drastically decreased in lasingefficiency in aqueous solutions or quenched altogether.

Since the refractive index of water changes relatively little withtemperature the search for ways of using this solvent has persisted withthe herein described invention as a result. According to this inventionit has been learned that the presence of certain additives in relativelylow concentrations in aqueous solutions of organic dyes hassignificantly enhanced their lasing efficiency.

In particular, this invention relates to the use of low concentrationsof various additives which function to prevent dye aggregation. Theadditives useful in the present invention include: I) hydrogen bondaccepting organic solutes typically in the concentration range of 0.1 to10.0 moles per liter of aqueous dyes solution. Typical hydrogen bondacceptors include: alcohols, ethers and polyethers such astetrahydrofuran and dioxane, phenols and the like; carbonyl compoundssuch as esters, ketones and amides (including urea and urea derivativessuch as guanidine salts, for example guanidine thiocyanate as well asheterocyclic analogs thereof such as 4-hydroxy, 6-methyl 1,3,3a,7-tetraazaindene); monoxides of group V and VI elements such asphosphineoxides, amine oxides, and sulfoxides, and II) both ionic ornon-ionic surface active compounds in concentrations near or above theircritical micelle concentrations, typically in the range of from about0.0005 to 0.1 moles per liter of dye solution. The following groups ofsurfactants are representative of compounds contemplated in II.

Anionic Surfactants, i.e., compounds which dissociate in water to form anegatively charged organic species that can form micelles, such ascompounds having the general formulae RA M where A represents an acidgroup; for example carboxylate, sulfate, sulphonate, and the like, thatis covalently bonded to R; and R is' a hydrocarb on residue containingat least 8 carbon atoms; and M can be hydrogen or an organic or aninorganic cation. Included in the foregoing general formulae arecompounds represented by the formulae 11-002? M and wherein R and M arethe same as hereinbefore described.

Cationic Surfactants, i.e., compounds which dissociate in water to formpositively charged organic specie that can form micelles, such compoundshaving the general formula RB X wherein B represents a tetravalent GroupV element, for example nitrogen, phosphorous and the like; or atrivalent Group VI element, for example oxygen, sulfur, and'the like,which is covalently bonded to an R which is as hereinbefore described,and X is an organic or an inorganic anion. Further, compounds having thefollowing formulae are included where R and X are the same ashereinbefore described.

Zwitterionic Surfactants, i.e., compounds which dissociate in water tomicelle-forming species that contain equal numbers of positive andnegative charges and have the general formula: ARB where A and R are thesame as hereinbefore described. Included in the foregoing generalformulae are compounds represented by the formula where R is the same ashereinbefore described. Non- Ionic Surfactants, i.e., compounds havingthe formulae fi6(6fH2CH20)nL no cinonomo L, a no CHCH L, aidftiibwherein R is the same as hereinbefore described, L is ahydrocarbonresidue and n is an average number between l and 100, and where EOrepresents a monoxide where E is a combined trivalent Group V element,such as nitrogen, phosphorous, and the like or a combined divalent GroupV] element other than oxygen, such as sulfur, selenium and the like,which are covalently bonded to R. Compounds included herein include polyalkylene oxides, glucosides, glycerylethers and monoxides, such asR-PO-CH RNO-CH RSOCH and RSOCH CH OH. R is the same as hereinbeforedescribed and L represents a hydrogen atom or a hydrocarbon residue.

Further functional groups which are useful as hydrogen bond acceptors inthe hereinbefore described Group 1 compounds are disclosed by T.Gramstad (Spectrochim. Acta, 19, 829-834, 497-508, 1963). Likewise,further surfactants useful in Group II are de scribed in ColloidalSurfactants, K. Shinoda et 21]., Academic Press, New York, 1963 andSolvent Properties of Surfactant Solutions, K. Shinoda, Marcel Dekker,Inc. New York, l967.

The dyes which are useful with the present invention will include mostorganic dyes capable of lasing and may extend to dyes which have not yetshown an ability to lase in organic solvent media. It is also expectedthat compound was Triton X- I00, a trademark of the Rohm & Haas Co. foroctyl phenoxy polyethoxy ethanol. 2 X

* Molar Dye was used in each case.

Example 1 was repeated as described except that the solution contained a2 X 10* Molar concentration of sulfo Rhodamine B dye and thedisaggregating compound was sodium lauryl sulfate.

u'ihgdyes will be useful in aqueous solution independent of their ioniccharge in solution. It is contemplated that useful dyes will includetriphenylmethane derivatives, phthaleins, azines, cyanines, and pyryliumdyes as well as their sulfur and nitrogen analogs.

The invention is further described by the following example.

EXAMPLE 1 The test apparatus consisted of a Sorokin-type coaxialflashlamp around a lasing cavity for optical excitation of the solutionscontaining Rhodamine 6G as described in US. application Ser. No.668,710, now US. Pat. No. 3,52l,l87 (French Patent No. 1,580,685, issuedJuly 28 l969), with the energy for the lamp stored by a Cornell Dubilierluf. fast discharge capacitor. The solutions were tested in 250 ml.quantities and were circulated through the laser cavity by means of apump while the tests were made. Thresholds recorded are the minimumvoltages on the capacitor required to initiate lasing. These thresholdsare:

Example 1 was repeated as described except that the dye was sulfoRhodamine B (2 X 10" Molar concentration) and the disaggregatingcompound was dodecyl dimethylamine oxide.

Example 1 was repeated as described except that the dye was sulfoRhodamine B (2 X 10 Molar concentra- Voltage Energy(=%C\/ 10"M R6G inEthanol 9 KV 40.5 joules l0M R66 in H,O l3.25-l4.25 KV 88-100 joules l0M R6G in H,O, 2M Urea 12.5 KV 78 joules l(lM R6G in H 0. 5% (weight 1 L0KV 605 joules Carbowux 4000' l(lM R in H 0, 5'; Carhowax l 1.0 KV 60.5joules l540' I0"M R60 in H O, with 15 ml lt.5 KV 66 joules Curbowax 600'added l0 "M R6G in H,O, 4% Oleyl Ester of Polyethylene Oxide l0.0 KV 5Ojoules Trademarks for Union Carbide Cu. polycthcrs.

EXAMPLE 2 Example 1 was followed as described except that the dye wassulfo Rhodamine B and the disaggregating tion) as? the disaggregatingcompound was 4- Hydroxy--methyll ,3,3a,7-tetraazaindene sodium salt.

Example 1 was repeated as described except that the dye was sulfoRhodamine B (2 X Molar concentration) and the disaggregating compoundwas hexadecyltrimethyl ammonium chloride.

Voltage Energy(=' CV) Dyc in water (250 ml) 19KV 180 joules Dye 0.375gof compound ZOKV 200 joules Dye 0.75g of compound 13.5 KV 91 joules Dye1.5g of compound 12.2 KV 74 joules Dye 3.75g of compound 12.2 KV 74joules EXAMPLE 7 Example 1 was repeated as described except that the dyewas sulfo Rhodamine B (2 X 10* Molar concentration) and thedisaggregating compound was 1,4,4- trimethyl-4-azoniahexadecanel-su1fonate.

Voltage Encrgy(=1CV) Dye in water (250 ml) 19.5KV 190 joules Dye 015g ofcompound 19 KV 180 joules Dye 0.40g of compound 16KV 128 joules Dye1.25g of compound l2.5KV 78 joules Dye 2.50g of compound 12KV 72 joulesDye 50g of compound 11,5 KV 66 joules EXAMPLE 8 1,1 '-Diethy1.oxadicarbocyaninc iodide (DODC) was tested to determine the effect of adisaggregating compound on the lasing threshold and efficiency of thedye. The'dye was optically excited with 5,300 A light from a frequencydoubled Nd-Glass laser. Pumping was done in a longitudinalconfiguration; that is, the pump light was passed through one of the dyelaser mirrors into the dye curvette along the optical axis of the dyelaser cavity formed by the two dielectric mirrors and the dye curvettecontaining the DODC. An attenuator was used to vary the input energy tothe dye curvette.

The pump light input energy was measured as well as the output energy ofthe laser light produced by the dye.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand, modifications can be effected within the spirit and scope of theinvention.

We claim: 1

1. In a dye laser having a laser cavity containing a laser dye solutionand an excitation means operably coupled therewith and capable ofproducing stimulated emission of the laser dye solution, the improvementwherein said laser dye solution consists essentially of a lasingconcentration of an aqueous-aggregating organic lasing dye in an aqueoussolvent containing a disaggregating compound selected from the groupconsisting of (a) an organic hydrogen bond acceptor compound selectedfrom the group consisting of an alcohol, a phenol, an ether, a carbonylcompound, a guanidine salt, a heterocyclic amide and an organic monoxideof a Group V or Group V] element and (b) an ionic or a non-ionic organicsurfactant capable of forming micelles in aqueous solution, saidsurfactant being selected from the group consisting of: anionicsurfactants having the formula RA M v cationic surfactants having theformula RB X r zwitterionic surfactants having the formula' ARB andnon-ionic surfactants having a formula selected from the group ofgeneral formulas consisting of:

wherein R is a hydrocarbon residue containing at least eight carbonatoms; A is an acid group covalently bonded to R; M is hydrogen or anorganic or an inorganic cation; B is the cation of a tetravalent Group Velement or a trivalent Group VI element; E0 is a monoxide where E is acombined trivalent Group V e1- ement or a combined divalent Group V lelement other than oxygen covalently bonded to R; X is an organic or aninorganic anion; L is a hydrogen atom or a hydrocarbon residue and n isa number between 1 and 100, and said compounds (a) or (b) being presentin an amount of 0.1 to 10 moles per liter of dye solution or 0.0005 to0.1 mole per liter of dye solution, respectively.

2. The dye laser as described in claim 1 wherein the guanidine salt isguanidine thiocyanate.

3. The dye laser as described in claim 1 wherein the carbonyl compoundis 4-hydroxy-6-methyl-l,3,3a,7- tetraazaindene.

4. The dye laser as described in claim I wherein the monoxide compoundis selected from the group con- X-lOO sisting of phosphineoxides,amineoxides and sulfoxides.

5. In a dye laser having (a) a lasing cavity containing a laser dyesolution and (b) an excitation means operably coupled therewith andcapable of producing stimulated emission of the laser dye solution, theimprovement wherein said laser dye solution consists essentially of alasing concentration of an aqueous-aggregating organic lasing dye in anaqueous solvent containing a disaggregating compound present in aconcentration range of from about 00005 to about 0.1 mole per liter andselected from the group consisting of:

anionic surfactants having the formula RA? M? cationic surfactantshaving the formula RB? X zwitterionic surfactants having the formulaAREfi and the group of general formulas consisting of:

wherein R is a hydrocarbon residue containing at least eight carbonatoms; A is an acid group covalently bonded to R, M is hydrogen or anorganic or an inorganic cation; 8 is the cation of a tetravalent Group Velement or a trivalent Group Vl element; E is a monoxide where E is acombined trivalent Group V element or a combined divalent Group V]element other than oxygen covalently bonded to R; X is an organic or aninorganic anion; L is a hydrogen atom or a hydrocarbon residue and n isa number between 1 and 100.

6. The dye laser as described in claim wherein the SOJGMGB 7. The dyelaser as described in claim 5 wherein the 10 cationic surfactant has ageneral formula R-N ing of polyalkylene oxides 8. The dye laser asdescribed in claim 5 wherein the 20 zwitten'onic surfactant has ageneral formula:

cm ll l( lli'(cllz)qsog l l or Q: 4 .i 9. The dye laser as described inclaim 5 wherein the non-ionic surfactant is selected from the groupconsisthaving the formula RO(CH CH O)L; glucosides; glyceryl ethershaving the formula ROCH -CHOHCH OH; monoxides of Group V and VI elementshaving the formulae R- POCH RSOCH or RSO-CH CH OH.

2. The dye laser as described in claim 1 wherein the guanidine salt isguanidine thiocyanate.
 3. The dye laser as described in claim 1 whereinthe carbonyl compound is 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene. 4.The dye laser as described in claim 1 wherein the monoxide compound isselected from the group consisting of phosphineoxides, amineoxides andsulfoxides.
 5. In a dye laser having (a) a lasing cavity containing alaser dye solution and (b) an excitation means operably coupledtherewith and capable of producing stimulated emission of the laser dyesolution, the improvement wherein said laser dye solution consistsessentially of a lasing concentration of an aqueous-aggregating organiclasing dye in an aqueous solvent containing a disaggregating compoundpresent in a concentration range of from about 0.0005 to about 0.1 moleper liter and selected from the group consisting of: anionic surfactantshaving the formula RA M ; cationic surfactants having the formula RB X ;zwitterionic surfactants having the formula ARB ; and non-ionicsurfactants having a formula selected from the group of general formulasconsisting of:
 6. The dye laser as described in claim 5 wherein theanionic surfactant has a general formula of R-CO2O M or
 7. The dye laseras described in claim 5 wherein the cationic surfactant has a generalformula R-N (CH3)3X ,
 8. The dye laser as described in claim 5 whereinthe zwitterionic surfactant has a general formula:
 9. The dye laser asdescribed in claim 5 wherein the non-ionic surfactant is selected fromthe group consisting of polyalkylene oxides having the formulaRO(CH2CH2O)L; glucosides; glyceryl ethers having the formulaROCH2-CHOH-CH2OH; monoxides of Group V and VI elements having theformulae R-PO-CH3, R-SO-CH3- or R-SO-CH2CH2OH.